Britain told Iran on Thursday it was happy to discuss its handling of street unrest after President Mahmoud Ahmadinejad accused its police of "savage" aggression against demonstrators, Reuters reported.
Britain helped lead Western condemnation of Iran's crackdown on protests against Ahmadinejad's re-election in June 2009. He was quick on Wednesday to criticise the British police's "crushing attack" on unarmed citizens.
In a letter to Iran's Foreign Ministry, Britain's top diplomat in Tehran said she hoped such openness would encourage Tehran to allow a U.N.-appointed investigator looking into alleged human rights violations in Iran to enter the country.
"I would remind you that the UK has a standing invitation to all U.N. special rapporteurs and has facilitated the visits of a number of these rapporteurs to the UK in recent years," British Charge d'Affaires Jane Marriott wrote, noting that Ahmadinejad had called for the United Nations to condemn Britain's action.
"I urge the Iranian government to extend a similar courtesy to the dedicated U.N. special rapporteur for the Islamic Republic of Iran, Ahmed Shaheed, to enable him to address the international community's grave concerns about ongoing human rights violations within Iran."
The U.N. Human Rights Council voted in March to nominate a special rapporteur for Iran to look into its crackdown on the opposition and frequent use of the death penalty.
Iran has so far declined to allow Shaheed, a former Maldives foreign minister, to visit.
Eight people were killed in protests against Ahmadinejad's disputed re-election in 2009. Two people were shot dead in Tehran on February 14 this year during the first opposition demonstration for more than a year.
Four people have been killed in the riots over the last few days in Britain which were initially sparked by the police shooting of a man. Three of the victims were killed when a car drove into them while trying to protect their area from rioters.